1. Field of the Invention
The present invention relates to a radiation-curable resin composition and a fingerprint-resistant resin composition including the same, and more specifically, it relates to a radiation-curable resin composition which is used to form a coating film on a surface of a metal, particularly, stainless steel, so as to provide the metal not only high-hardness but also excellent physical properties such as close adhesion to a base, scratch resistance, light fastness, heat resistance, flexural processability and a fingerprint-resistant bonding property, and a fingerprint-resistant resin composition including the same.
2. Discussion of Related Art
Stainless steel is a very important material in current industries, which has an advantage in that the surface of the material has an innate metallic texture without any surface treatment such as painting due to its high resistance to corrosion, which is one of the characteristics of stainless steel. Thus, stainless steel has been widely used for kitchen sinks, cookware and tableware, and also it has been used as a construction material such as a material used for building the exterior of the building, and in elevators and escalators. In addition, stainless steel has been widely used as an industrial material for chemical and petrochemical facilities, food and medical equipment, drinking water and wastewater disposal plants, automobile and airplane parts, etc.
In particular, stainless steel has been prepared by adding a certain amount of chromium (11% or more) to a general steel so as to give an elegant metallic texture and to prevent discoloration and corrosion. This was developed in the early 20th century and it has been named “stainless steel” to distinguish it from other forms of steel. Heretofore, stainless steel has been produced into over 100 products, and it has been classified in a variety of ways in the metallographic aspect.
As such, stainless steel is prepared by alloying two or more components so as to solve the problem of corrosion, which is one of the major drawbacks of iron. Thus, stainless steel, depending on the surface treatment, has been generally used for high-gloss products with mirror-like surfaces, brush patterns and designable products through an etching process.
Meanwhile, there has been an increasing demand for stainless steel having good metallic texture and excellent appearance as consumers' demands for better products is increasing with recent technical developments. Although, conventional stainless steel has an excellent metal metallic luster, it has a problem in that it is vulnerable to contamination. Therefore, recently, further technical development is being called upon to solve this problem.
As one example, a method of coating the surface of a metal, particularly, stainless steel, with an oil-type polyester-melamine-curable resin composition is mainly used to prevent or reduce contamination by fingerprints.
However, the conventional oil-type resin composition, that is paint, contains a material that causes contamination of the atmosphere and global warming, and thus there is a need to solve the problem in an environmentally friendly manner.
Therefore, to solve the aforementioned problems, a method using a radiation-curable resin composition which is environmentally friendly and can be mass-produced has been developed. A radiation-curable resin composition, particularly ultraviolet (UV) ray-curable, that is paint, was developed in Korea and further developed and widely used for applications such as wooden and plastic materials, starting from the development of a radiation-curable paint for paper, particularly, a UV-curable paint in the early 1980s. However, the development of a UV-curable paint with respect to metals has been intermittently made due to its poor adhesive strength and poor processability caused by rapid curing and radical polymerization, which are innate characteristics of the UV-curable paint, and the technical development of the UV-curable paint has limits.
In particular, a thermosetting paint has been partly used as a coating material of the resin composition used for stainless steel to show colors, but it is known that some coating materials for preventing contamination of stainless steel kitchen appliances have been developed recently.
Meanwhile, more so abroad than in Korea, research on a technique for applying a UV-curable paint for metal materials has been continuously done to work towards an environmentally friendly paint concept. In recent years, there has been a steady attempt to apply this technique to top coat automobiles, etc.
In particular, it is known that a fingerprint-resistant UV-curable paint was developed to solve contamination, which is a drawback of stainless steel, and some products were produced and sold by the first half of 2006.
Therefore, as examples of the techniques for treating a surface of stainless steel with the above-described radiation-curable resin composition, particularly UV-curable, US Patent Application Publication Nos. 2004-0225039 and 2007-0016947 disclose that a hydrolysis-resistant, scratch-resistant and anti-contamination coating layer is formed by directly applying a resin composition to a metal or plastic surface and crosslinking the resin composition with radiation, particularly, UV rays. However, the resin composition has problems in that the processability and adhesivity, which are the most important physical properties of a steel product, are deteriorated.
As other examples, US Patent Application Publication No. 2006-0110537 discloses a fingerprint-resistant coating structure including a layer formed of a material selected from the group consisting of a hydrophobic nano-compound, an oleophobic nano-compound and a super-amphiphobic nano-compound, Japan Patent Publication Nos. PEI11-43627 and PEI11-124514 disclose a radiation-curable resin composition including an acrylic acid ester of a bisphenol A diglycidyl ether polymer, and Japan Patent Publication No. 2005-054029 discloses a coating composition including an active energy ray-curable polymerizable monomer having a main chain in which the hydrogen in an alcoholic hydroxyl group is substituted with an alkaline metal atom. However, the above-described prior arts have problems in that the techniques are for plastic and they are difficult to apply to metal, particularly stainless steel, which requires adhesive strength and pliability.